by Ted Berg, USA TODAY Sports

by Ted Berg, USA TODAY Sports

CLEARWATER, Fla. â?? Phillies starter Cole Hamels threw off flat ground on Sunday as he works to recover from the biceps tendinitis that will likely delay the start of his season. Hamels is slated to throw his first bullpen session of the spring on Tuesday.

"It was very encouraging," Hamels said. "Building up arm strength is key, and finally getting to the point where you're focusing on not just trying to build arm strength, but building accuracy."

New Phillies pitching coach Bob McClure watched Hamels throw.

"Good, really good," McClure said when asked about the lefty's progress. "Free and easy."

"I feel comfortable that nothing is painful," Hamels said. "I'll probably make some better strides once we get into games, seeing where I'm at."

Hamels signed a six-year, $144 million contract extension with the Phillies before the 2012 season. He has been durable throughout his career, making at least 31 starts in each of the past six seasons.

But with his spring schedule about 1-2 weeks behind, according to McClure, Hamels might not be ready to start by opening day on March 31.

"Unfortunately it's a little bit later than I want," said Hamels, who expects to start a typical spring training schedule with his next session after the upcoming bullpen work. "Going out there and not being 100 percent is not going to help us win."

McClure said Hamels will throw 28-35 pitches off the mound on Tuesday.